jquery获取图片真实宽高

var pic_real_width, pic_real_height;
$("<img/>") // Make in memory copy of image to avoid css issues
    .attr("src", $(img).attr("src"))
    .load(function() {
        pic_real_width = this.width;   // Note: $(this).width() will not
        pic_real_height = this.height; // work for in memory images.
    });

即将图片在内存里读取一遍即可。

jQuery中循环的每一个功能等待完成,然后再继续循环

First of all, jQuery 1.4 added the delay function, which I assume is what your custom wait implementation is doing.

Using delay, you can sort of fake the functionality of each element “waiting” on the previous element to finish by using the first parameter to the each callback as a multiplier for an intial delay. Like this:

var duration = 5000;

$('elem').each(function(n) {
    $(this).delay(n * duration).fadeIn().delay(duration).fadeOut();
});

So the first element will fadeIn immediately. The second will fadeIn after 5,000 ms. The third after 10,000 ms and so on. Keep in mind that this is faking it. Each element is not actually waiting on the previous element to finish.